A nomogram to evaluate intrinsic absorption rate constants of potential oral prolonged-release candidates.

The purpose of this study was to devise a simple method to determine whether or not a drug's absorption rate constant favored the selection of that drug for an oral prolonged-release drug delivery system (DDS). Computer simulations were used to observe the drug time-course in the DDS, the gastrointestinal tract, and the cumulative amount absorbed following administration of an 8-, 12-, and 24-hr zero-order DDS. For each DDS, the drug's intrinsic absorption rate constant, ka, was systematically varied from 0.

Influence of pH, temperature and buffers on cefepime degradation kinetics and stability predictions in aqueous solutions.

First-order rate constants (k) were determined for cefepime degradation at 45, 55, 65, and 75 degrees C, pH 0.5 to 8.6, using an HPLC assay.

A kinetic oxymoron: concentration-dependent first-order rate constants for hydrolysis of ceftazidime.

The influence of pH, temperature, and buffers on the hydrolysis of 10(-4) M ceftazidime was previously reported. The pH-rate profiles showed that maximum stability occurred in the pH-independent region from 4.5 to 6.

A nomogram to predict the best biological half-life values for candidates for oral prolonged-release formulations.

It is sometimes possible to maintain plasma concentrations between desired maximum and minimum limits by repetitively administering a drug in an oral prolonged-release formulation when this goal cannot be achieved with a rapid-release formulation. However, this approach does not work with all drugs. The biological half-life value of the drug can be one cause for failure of this approach.

Influence of pH, temperature, and buffers on the kinetics of ceftazidime degradation in aqueous solutions.

First-order rate constants (k) were determined for the hydrolysis of ceftazidime in the pH range of 0.5 to 8.5 at 45, 55, and 65 degrees C by a stability-indicating HPLC assay.